Psychrometrically controlled air cooling system



June 1942- R. J. PALMER 2,287,268 PSYCHROMETICALLY CONTROLLED AIR COOLING SYSTEM Filed May 18, 1940 i Room I OR. I ZONE l I 17 P-@ -Ekj j 1 CENT/2H1. OUTDOOR DEHuMm/ /ER, AIR

- To @QSJ'AZ m 24 '20 lTo 77 1A 1 osr/1T /6' INVENTOR Patented June 23, 1942 ,rsrcnnommarcmr CONTROLLED AIR coonme srs'rrm Robert T. Palmer, Sharo Sturtevant Comp 11, Mass, asslgnor to n. r. any, Boston, Mass.-

Application May18, 1940, Serial No. 335,96'l

4 Claims. ((1236-44) This invention relates to the automatic con- I trol of air cooling systems and relates more particularly to the thermostat and hygrostat control of air cooling systems utilizing local air recirculation units. I

For certain types of air cooling installations, it is preferred to dehumidify the air ata central point, to supply the dehumidified air under substantial static pressure to local recirculation units utilizing ejectors, in thegooms-to be servedand supplying the dehumidihed air to the electors to induce the flow of room air as recirculated air I through the units to be mixed therein with the dehumidified air. In such systems, it is usual Lto take care of local sensible heat changes by adjusting the temperature of local sensible coolers in the recirculated air stream. This invention provides improvements in such systems.

- A feature of this invention resides in adjusting the volume of dehumidified air supplied to a local room or zone conformably with humidity changes therein and coordinately therewith adjusting the volume of recirculated air for maintaining a substantially constant volume in the air circulated through the local room or zone. Another feature of this invention residesin adjusting independently the volume of dehumidified air supplied to each of a plurality of local ejector units conformably with humidity changes in the local rooms or zones supplied thereby, and

sure supply source to maintain a substantially constant static pressure.

The invention will now be described with ref.- I

erence to the drawing, of which:

Fig. 1 is a schematic view or an air conditioning system embodying this invention, and

Fig. 2 is aschematie view illustrating another way of controlling the volume ofrecirculated air entering a local recirculation unit.

The rooms or zones 5, contain the local air ejector units 6 which may be of the general type disclosed in the U. S. Patent No. 2,000,597 which issued May 7, 1935 on an application of R. E.

Keyes. Each-unit G'contains the ejector formed by the nozzles I, a recirculated air inlet containing the air cooler 8 and the air outlet 9.

'The central fan lflforces outdoor air under pressure through the central dehumidifier 'H and then through the supply ducts l2 to the ejectors in the units 6. The branch duct to each unit contains the damper I! for varying the vol ume of dehumidifled air supplied to the units. The main duct l2 contains a pressurestat ll for adjusting through the motor IS, the spin nducing vanes I6 in the inlet of the'fan l0 ior maintaining a constant air pressure in the-supply duct.

vThe fan I0 is preferably of the type disclosed in the U. S..Patent No. 1,989,413 issued-Ian. 29,

1935 on-an applicatiomof H. F. Hagen.

Each room or zone I contains athermostat,

l1 and a hygrostat l8 for maintaining the desired local air conditions. The thermostats ll control themotors 19 which adjust thevalves 20 in the refrigeration supply linosll to the coolers 8, and adjusts the temperature of. eachcooler conformably with local sensible heat;.variations and thus takes care of local sensible heatgains without the necessity ioradjustmentof the temperature of the dehumidifled air from the dehumidifier ll. v Y

The hygrostats it by adjustment of thedampers i3 by means of the motors 22, vary thevolume of dehumidiiied airreaching the velectors conformably with local relative humidity changes. This satisfies ventilation requirements for it may be demonstrated that in an air humidity changes conformably' with the number of occupants. It is desired however, to maintain as near as possible, a substantially constant volume 01' air circulated t e units 0; Adjustment by the dampers ll, of the volume of air cooling system with a human load, the relative so to the ejectornozzlesl also adjusts-the total coordinately therewith adjusting the air'pre'svolume of air since .it'ail'ects the ability of the 'ejectors to induce the flow of recirculated air.v

Accordingly in the embodiment of Fig. 1-, when the dampers l3 are adjusted by the hygrostats I! to increase the volume of air to the units 6, the motors 23 are actuated to adjust the spacing of the ejector nozzles 'l to move them further apart thereby decreasing the ejector action and decreasing the volume of recirculated air.

In-the embodiment of Fig. 2, instead of ad justing the ejector nozzles when the volume of air to the units is varied by adjustment of the dampers IS, the motors 24 adjust the dampe.s

'fecting the performance oi the electors in the other unit or units, the pressurestat ll adjusts through the motor IS, the vanes it in the inlet aasmea in the air from said dehumidifier to said eiecton and-means including spin inducing vanes in the inletof said fan for varying the pressure in the air supplied by said ran coniormably with pressure changes in the air between said dehumidifier and said ejector.

3. An air conditioning system comprising a I central. source for supplying conditioned air to the fan II to cause it to maintain a constant air pressure in the air supply duct to the units. While one embodiment of the invention has been described for the purpose of illustration, it

should be understood that the invention is not limited to the exact apparatus and, arrangement of apparatus illustrated as modifications thereof may be suggested by those skilled in the art without departure from the essence of the invention.

What is claimed is:

1. An air conditioningsystem comprising a central dehumidifier, .a local. sensible cooling unit, means forming a recirculated air inlet into said unit, an ejector in said unit connected to said dehumidifier for inducing the flow of recirculated air through said inlet under the action of air from said dehumidifier, means for varying the volume of air from said dehumidifier conformably with humidity changes in the space -served, means including a fan for maintaining a static pressure in the air irom said dehumidifier to said ejector, and means including spin inducing vanes in the inlet of said fan for varying the pressure in the air supplied by said fan conformably with pressure changes in the air between saiddehumidifier and said ejector.

2. An airconditioningsystem comprising a central dehumidifler, a local sensible cooling unit, means forming a recirculated air inlet into said unit, an ejector in said unit connected to said dehumidifier'for inducing the flow of recirculated air through said inlet under the action of air from said dehumidifier, means for varying the volume of air from said dehumidifier coniormably with humidity changes in the spaces served, means for varying the volume of recirculated air through said inlet by decreasing the volume of recirculated air upon an increase in in the volume-of conditioned air thereto, its air the volume of dehumidified air and by increasing the volume of recirculated air upon a decrease in the volume of dehumidified air, means ineluding a fan for maintaining a static pressure under pressure, a local recirculation unit having an air outlet in the conditioned space and having a primary air inlet in its base, a duct connecting said inlet and said 1:, means forming a recirculated air inlet a side wall of said unit, a sensible cooler in said unit in alignment with said recirculated air inlet, means iorming an elector in said unit between said inlets i'or inducing the dew oi recirculated air through said recirculated air inlet therethrough, damper means in both of said inlets, and means including local, psychrometrically central source for supplying conditioned air under pressure, a local recirculation unit having an air outlet and a recirculated air inletin the conditioned space, an elector in said unit connected to said source for inducing the flow of recirculatedair into said inlet through the fiow of the conditioned air from said source, and for discharging the mixed air through said outlet,

-means including local psychrometrically responsive means for varying the volume'oi' air supplied from said source to said ejector, and means for soadjusting said ejector that upon an increase inducing action is decreased and upon a decrease in the volume of conditioned airthereto, its air inducing action is increased whereby at all times a substantially constant mixed air volume is supplied through said outlet.

' ROBERT T. PALMER.

and said cooler. through the ilow of primary air from said source 

